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Xti2000 -Cerwin Vega mains - Driverack PA+ HELP


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#1 HipShot24

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Posted 12 May 2012 - 09:56 AM

hello all, new to Crown forums and new to sound reinforcement so please try not to laugh too hard as I have searched the forums now to find anything more specific to my needs. first, my system:

MAINS

(2) Cerwin Vega CVP 2153 tops (full range) 4 ohm nominal
(2) Cerwin Vega AB36C Afterburner Subs   8 ohm nominal
(4) Crown Xti2000 power amps.  (one for each cab)
Driverack PA+
Allen & Heath MixWiz3 16:2:1

MONITORS

(2) Crown Xti2000 power amps (one ch for 2 cabs ea jumped from mon to mon)
(4) Cerwin Vega Cvi 122 monitors
(2) Yamaha club series V (15 & horn) (one channel per cabinet)

my questions: (it goes without saying that I want to use this system to the optimal efficiencies)

1. how should I set up my presets on the Xti2000 for the tops
2. how should I set up my presets on the Xti2000 for the subs
3. do I need to "RE-wire" my neutrik cables?
4. Xti2000s on the tops...should they be "linked" and then jump from one cab to the other for a 4 ohm load?
5. Should I "link" the 2 Xti2000s on the subs and then jump from one cab to the other?
5. if YES to 4 and 5, HOW is this accomplished? I have only heard the term "link"...not sure what it means.
6. Do I need to RE-WIRE my neutrik cables in any form or fashion as i'm certain the music store gave them to me off the shelf

I have been running all of the MAINS power amps in bridge mono but the thing is, with the way that I have it set up it sounds "ok"...a friend has the exact same mixer, driverack and poweramps in his set up and we used MY speakers on his setup and it sounded INCREDIBLE! NOT "ok" like mine but WOW!!! it HAS to be something in the way my poweramps are set up right? I realize the driverack is just as important but I set it up with the wizard but had to use a "custom" setting for the speakers.  tops in stereo and subs stereo as well because i'm using both L and R outs on the driverack on tops and subs and, of course, coming out of the mixer from L and R outs to L and R inputs on the driverack.

WOW, sorry for all the questions but i'm new to the "Sound" game. that's why good engineers are worth their weight in GOLD!!


CVP 2153 tops
Dual Cerwin-Vega 15" woofers and 44mm diaphragm tweeter
  Frequency Response: 37 Hz - 20 kHz / 134 dB SPL
Power Capacity: 1000W RMS / 2000W Program / 4000W Peak
Recommended Power: 1500 w - 2000 w
Sensitivity (1w/1m): 101 dB
Nominal Impedance: 4 ohms

AB36C AfterBurner Subs
Frequency Response: -3db 40 Hz - 310 Hz / -10db 33 Hz - 350 Hz
Power Capacity:
800W RMS / 1600W Program / 3200W Peak

Recommended Power: 1200 w - 1600 w @ 8 ohms
Input Connectors: Phono, Speakon
Sensitivity (1w/1m): 108 dB
Nominal Impedance: 8 ohms
Maximum SPL: 140 dB



#2 dakos

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Posted 12 May 2012 - 02:05 PM

Welcome to the forums,
Don't hesitate to ask newbie questions, better to be uncertain here then to be frustrated during a gig.
I started to answer your questions one after the other and I understood there are too many weak links in your rig.
First, XTIs are great amps, but when you operate them bridged into 4 ohm load, you're just asking for trouble, I don't know how to avoid that since you have very powerful speakers, tops or subs and only XTI2000 amps. My best advice to you for the tops and subs is sell the XTIs and get amps powerful anough for these speakers in stereo at 4 ohms per channel, the IT6000/8000 are great for that and their price used is very reasonable. My guess is that your friend has an amp that can do that and that's why your speakers sounded better when connected to his rig.

You shouldn't configure your subs to work in stereo, use the DRPA+ and configure them in signal summing mode or whatever DBX decided to name this feature.

Make sure you have thick cables, 10AWG and don't daisy chain them, run a separate cable to every speaker at least for the subs and tops. On XTIs that are configured for bridge mode you need to rewire the amp side connector as explained on page 13 of the manual.

There are many more little tweaks to make it sound better but I think you should start from the simplest configuration, just two full range speakers, the amps needed to power them without any preset (DSP off), a mixer and a signal source, now see if you like the sound.

What settings did you use for crossover? How did you operate your speakers when you connected them to your friends rig (full range, with subs)? What processing does he have?

#3 HipShot24

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Posted 12 May 2012 - 06:05 PM

[/quote]
What settings did you use for crossover? How did you operate your speakers when you connected them to your friends rig (full range, with subs)? What processing does he have?
[/quote]

I appreciate your help here!!  I am a total idiot with this stuff...

my x-over is set at 100 and 40 & below is dropped out altogether on the driverack... running full range on tops BUT only one Xti2000 per top. Cerwin Vega recommends an amp that can deliver 1500 to 2000w. crown says the Xti in bridged to mono  will deliver 2000w... from a purely academic view, Shouldn't the power be sufficient?

(not sure of the processing that my buddy used other than I know he was using the same mixer, power amps, and driverack PA+ ...other outboard gear was simply gates and limiters and fx units. It was pretty much the exact same rig except his speakers that he normally carries are JBL's. system wizard setup for the driverack was set for the JBL's which were the 718s (I think) single 18s anyway at the same watts and ohms as my afterburners and tops very similiar to my CV's. so we didn't re-set it for my speakers and left it alone, mainly because they don't have afterburners in the DriveRack's yet) that and the cables from the power amps must have been wired correctly and mine are not, resulting in what exactly I'm not sure??? I wonder if its a LACK of power because I'm not getting a true "bridge" signal?? could this be the culprit?

I am running separate cables to each cab and not daisy chaining at all ...so does that mean that the subs are receiving only half the power of the amp (stereo signal from ch-1)  running 8 ohms because I am (A) using the normal wire configuration or (cool.gif not using banannas and going from both red posts?  SO, even though I have the preset on bridge or bridge mono, i'm NOT getting the full strength I'm guessing????

as far as running the subs in stereo now here's the deal on that, (and I know you may wanna b***h slap me for being stupid but here goes)....I'm coming out of the mixer from L and R outs, going to driveRack L and R in's.

the outputs from the DriveRack are L and R Low out to the subs  and L and R out to tops (running in full range). How else would I configure that. Doesn't seem that it would hurt anything like that and honestly, I can't see how any other way would improve the performance?? I suppose I could simply come out of the DriveRack L out to the first sub power amp, link that power amp to another and run two cables (already using two) to each sub but that that doesn't seem to matter as I would only be pulling the R-output cable out of the DriveRack  and bringing the same signal to the other sub amp from the first sub amp and giving it a "mono" signal. I'm not sure that the subs ran in my current config is not more of a L and R  than they are true stereo?  

From what you've said so far, I should probably re-wire the power amp end of the two sub cables for sure to run bridge or bridge mono, should I also re-wire the tops' power amp ends?

as for other amps.... that take MONEY of which OPEC gets most of mine! would love to have a few crown macro's but they don't seem to be giving those bad boys away and we haven't found any grants by Harman that gives to charaties yet :-)

#4 dakos

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Posted 12 May 2012 - 10:43 PM

QUOTE(HipShot24 @ May 12 2012, 06:05 PM) View Post
I appreciate your help here!!  I am a total idiot with this stuff...

We all felt like that at some point in our career.
QUOTE(HipShot24 @ May 12 2012, 06:05 PM) View Post
my x-over is set at 100 and 40 & below is dropped out altogether on the driverack... running full range on tops BUT only one Xti2000 per top. Cerwin Vega recommends an amp that can deliver 1500 to 2000w. crown says the Xti in bridged to mono  will deliver 2000w... from a purely academic view, Shouldn't the power be sufficient?

What about the crossover for the tops? if you have the subs crossed at 40hz HPF (high pass filter) and 100hz LPF (Low Pass Filter), then you should cross your full range tops at about 105hz HPF otherwise you will get cancellations in the 40-100hz range and you will suffer from terrible low end. Also write to me the slopes you were crossing over everything.

Now for power demand, every system should allow for some headroom for transient peaks in the music, speakers have headroom built in them while amps almost have none. When you take an amp that the maximum wattage rating is good for the speakers continuous music rating, that's not going to be enough. When you were trying to match your speakers to the amps, you were comparing the 4 ohm bridge rating of the amp, which is almost never a continuous rating.
You should continue reading here:
http://www.crownaudio.com/amp_htm/amp_info..._much_power.htm
and here:
http://www.crownaudio.com/forums/index.php?showtopic=3838
QUOTE(HipShot24 @ May 12 2012, 06:05 PM) View Post
(not sure of the processing that my buddy used other than I know he was using the same mixer, power amps, and driverack PA+ ...other outboard gear was simply gates and limiters and fx units. It was pretty much the exact same rig except his speakers that he normally carries are JBL's. system wizard setup for the driverack was set for the JBL's which were the 718s (I think) single 18s anyway at the same watts and ohms as my afterburners and tops very similiar to my CV's. so we didn't re-set it for my speakers and left it alone, mainly because they don't have afterburners in the DriveRack's yet) that and the cables from the power amps must have been wired correctly and mine are not, resulting in what exactly I'm not sure??? I wonder if its a LACK of power because I'm not getting a true "bridge" signal?? could this be the culprit?

I don't think that is the culprit but if you like the sound coming out of his system with your speakers then you should copy his settings and cable configuration exactly.

QUOTE(HipShot24 @ May 12 2012, 06:05 PM) View Post
I am running separate cables to each cab and not daisy chaining at all ...so does that mean that the subs are receiving only half the power of the amp (stereo signal from ch-1)  running 8 ohms because I am (A) using the normal wire configuration or (cool.gif not using banannas and going from both red posts?  SO, even though I have the preset on bridge or bridge mono, i'm NOT getting the full strength I'm guessing????

Yes, you are correct.

QUOTE(HipShot24 @ May 12 2012, 06:05 PM) View Post
as far as running the subs in stereo now here's the deal on that, (and I know you may wanna b***h slap me for being stupid but here goes)....I'm coming out of the mixer from L and R outs, going to driveRack L and R in's.

the outputs from the DriveRack are L and R Low out to the subs  and L and R out to tops (running in full range). How else would I configure that. Doesn't seem that it would hurt anything like that and honestly, I can't see how any other way would improve the performance?? I suppose I could simply come out of the DriveRack L out to the first sub power amp, link that power amp to another and run two cables (already using two) to each sub but that that doesn't seem to matter as I would only be pulling the R-output cable out of the DriveRack  and bringing the same signal to the other sub amp from the first sub amp and giving it a "mono" signal. I'm not sure that the subs ran in my current config is not more of a L and R  than they are true stereo?

In the DR you have to choose if you want a 2X4 or 2X3 operation, you should choose the 2X3 and then you will have a summed signal, that's dual mono signal out from your separate left and right connections.
QUOTE(HipShot24 @ May 12 2012, 06:05 PM) View Post
From what you've said so far, I should probably re-wire the power amp end of the two sub cables for sure to run bridge or bridge mono, should I also re-wire the tops' power amp ends?

Yes, you should rewire every cable on any amp you run at bridge (=bridge mono).
QUOTE(HipShot24 @ May 12 2012, 06:05 PM) View Post
as for other amps.... that take MONEY of which OPEC gets most of mine! would love to have a few crown macro's but they don't seem to be giving those bad boys away and we haven't found any grants by Harman that gives to charaties yet :-)
sad.gif

#5 HipShot24

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Posted 12 May 2012 - 11:01 PM

clouds are lifting my brother! thank you so much for taking the time out of your saturday evening to help me out!!! I have some work to do and its well that I get to it!! thank you a thousand times my friend!! i'll be sure to post once i have reconfigured my system

#6 HipShot24

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Posted 13 May 2012 - 11:31 AM

AMAZING DIFFERENCE!!!!! THANK YOU!!!!

I have a lot of learning to do but hopefully I won't FRY anything in the process of it. Even though the Xti2000's are a bit small for the cab's it's all I have to work with at the moment until I can save up enough for a few Macro's! thanks again for all your help. These things will now thump so hard that the whole house shakes! the amps aren't even working hard to get there either. The driverack is a miraculous device! sure wished we had those things 20 years ago! not to mention the correct wiring on the subs